Explosively formed water jet disruptors use high explosives, typically a shaped plastic explosive, to create a shock wave traveling through water or some other liquefying medium to collapse onto a forming cavity. This shock wave collapse by its geometry and the dynamic transit of the shock wave along the forming can create a supersonic jet of water that is ejected from the system. These supersonic water jets can be used to penetrate through walls such as mild steel plate that is over an inch thick. A very useful application, because the water jet it's non-sparking generating penetration, is to disrupt improvised explosive devices by severing the explosive sequence system and dispersing the improvised device explosives without detonating their explosives Prior art explosively driven water jet disruption systems have had a host of problems that have hampered demolition workers:
Blasting Cap Problems:
                Blasting caps not touching plastic explosive—leading to misfiring.        Blasting cap penetrations that are too deep into plastic explosives can cause two shock waves and waste explosive energy, which poorly drive the explosion shock front coupling into the water jet.        Off axis initiation due to a non-centered blasting cap leads to asymmetric and inaccurate water jets.        Blasting caps come in multiple diameters and may not fit, or slip out of holders.        Disarming by removing the blasting caps from plastic explosive and can leave a cavity in the plastic explosive. The subsequent rearming may require further pressing of the blasting cap into the plastic explosive, or result in non-contact. Non-contact can cause poor coupling of the blasting cap to the plastic explosive, resulting in asymmetric detonation, or non-initiation.Shaping Plastic Explosive Problems:        The cutting and shaping of a precise quantity of plastic explosive can be time consuming and not exact. Leading to uncertainty of the explosive drive and effect.        The use of PETN to detonate the explosive has led to non-uniform burns since it is molded around the explosive by hand.Water Filling Problems:        Gravity filled and open ended devices are not flexible to position        Displacement of water while assembling a sealed system can lead to pressurization of the water and deformation of the jet forming cavity.        Bubbles or under filling of coupling water can lead to non-uniform shock coupling and imprecise jet forming.Cone Positioning Problems:        It has been observed that if the jet forming cavity cone in the coupling water touches the plastic explosive that there was poor shock coupling and the subsequent jet is malformed.        It has been observed that if the jet forming cone in the coupling water was more than ¼ inch away from the plastic explosive the shock coupling was poor and the jet was malformed.Cone Shaping Problems:        Asymmetric cones have led to poor jet forming.        If the thin wall cone is collapsed due to the water pressure the resulting shock jet can be miss formed and reduced power delivery and accuracy.        Forming the jet forming cavity out of plastics and thicker walls, other than thin walled polyethylene produced weak jets.Disruptor Positioning Problems:        Alignment of the jet forming cone to intended target can be in accurate.        Uneven surfaces near or on the intended targets can lead to poor positioning        The alignment to a guide laser beam needs to be precise enough to align and use to 1.7 cm diameter water jet propelled over a 274 cm distance, (0.7 inch diameter water jet over 9 ft) (+−0.072 degrees).        The target can be imaged with x-rays and a guide beam arranged to point at the precise component that needs to be disrupted to disable the target, thus the disruptor needs to have a mechanism to allow for alignment using the guide laser beam, gun sight, or telescope.Remote Targeting Problems:        Robots are expensive and can be destroyed by explosions        The Robots can be source of metal shrapnel.        Robots are needed in uncertain and dangerous disruption situations.Heavy Metal Problems:        Metal containers can lead to dangerous shrapnel and spark generation.        Metal debris can interact with the environment and lead to more cleanup, while plastic debris can degrade and be environmentally inert.Cutting and Shaping the Plastic Explosives Problems:        The cutting and forming of the plastic explosive needs to be precise, to deliver a precise shock wave.        Poor shaping or under or over fill has led to poor jet forming.Clarity and Loss of Instructions Problems:        Instructions need to be explicit and understandable        Instructions need to be with the disruption device and not lost in the field.        The instructions need to be destroyed with explosively driven water jet disruptor to avoid littering and perhaps informing adversaries.        
Needs exist for an improved explosively driven water jet former and delivery system.